Redundant Array of Independent Disks (RAID) is a hard disk group (logic hard disk) formed by combining multiple independent hard disks (physical hard disks) in different manners, thereby providing a better storage performance than that of an individual hard disk and providing data backup technology.
When a user needs a storage space, he/she may apply to a server or a storage space management system to obtain a storage space with a corresponding capacity. Specifically, when the user applies to create a storage space, a disk region of a corresponding size is divided from a group of fixed disks as the storage space requested by the user; a RAID group is created based on the divided disk region, and this portion of disk region is divided into multiple blocks (e.g., 1 MB for each block), wherein metadata for describing a state of each block is stored at the end of this portion of disk region, and information for describing RAID configuration is stored in the storage space of the memory.
However, when the storage space is created in the above manner, all I/O operations for the created storage space need to access or update the stored metadata. Thus, the storage manner of metadata will become a bottleneck of the whole mapped RAID traffic. For example, when the disk storing metadata is damaged, it is certain to fail the whole RAID mapping, thereby resulting in reduced reliability of data storage; in addition, the user cannot expand or reduce the size of the storage space on the basis of the storage space that has already been applied for.